* {
    margin: 0;
    padding: 0;
}

html,
body {
    width: 100%;
    height: 100%;
}

#root {
    width: 100%;
    height: 100%;
    position: relative;
}

.tag {
    width: 200px;
    height: 200px;
    background: #900;
    position: absolute;
}